A University of Missouri study finds that computer users react more positively to images that they do not control.

"What we found -- contrary to the assumption -- was that people actually paid more attention if they didn't have control and, for the most part, rated those pictures as more arousing and pleasant," said Kevin Wise, an assistant professor of advertising.

Wise and Byron Reeves, a professor at Stanford University, studied the reactions of 22 students to images they controlled with a mouse and to images that appeared on screen unexpectedly.

They found that the students rated the unexpected images more positively. They also found that after the unexpected images appeared, the students demonstrated "heart orienting," a slowing down of heartbeat that is a sign that someone is concentrating.

Wise said "heart orienting" is a hard-wired response, presumably because early humans needed to focus on the unexpected in their environment. He said people generally like routine and control with a mix of the unexpected.

Copyright 2006 by United Press International